Wireless communication has continued to develop since its introduction, and is still developing by providing more bandwidth for more performance and more services. Channel estimation and equalization are used in wireless communication to handle effects that are intrinsic to a wireless channel, such as a variation in channel characteristics during communication. To support channel estimation in base stations and user terminals, wireless communication standard define so-called pilot sequences, allowing the base stations and user terminals to perform channel estimation by correlation received signals with known pilot sequences, and to derive a channel estimate from the correlation. Channel estimation is used in GSM as well as WCDMA wireless communication.
GSM (Global System for Mobile Communications, originally Groupe Spécial Mobile) has been a success since quite many years and has been developed over time to have more performance and provide more services. GSM networks operate in a number of different carrier frequency ranges, known as so-called 2G (GSM frequency ranges) and 3G (UMTS frequency bands). Regardless of the frequency band selected by an operator, the frequency band is divided into timeslots for individual phones to use. This allows eight full-rate or sixteen half-rate speech channels per radio frequency. These eight radio timeslots (or eight burst periods) are grouped into a Time Division Multiple Access (TDMA) frame. In TDMA, a timeslot is the basic radio resource used to facilitate communication between the handheld device and the base. Some of the bits (or symbols) that are transmitted during the time slot are known at the receiver side, and may be used in order to estimate the channel between the handheld device and the base station. Further, GSM uses General Packet Radio Service (GPRS) for data transmissions like browsing the web.
Third generation wireless communication has also developed to use Wideband Code Division Multiple Access (WCDMA or W-CDMA) communication. WCDMA is used by the Universal Mobile Telecommunications System (UMTS) family as was developed and maintained by the 3rd Generation Partnership Project (3GPP). It allows to achieve higher speeds and to support more users compared to time division multiple access (TDMA) and time division duplex (TDD) schemes used earlier.
A processor at the receiver side of a GSM or W-CDMA is usually arranged to perform channel and noise estimation to obtain an estimated channel response and an estimated noise variance by correlating a received signal (usually after some pre-processing) with one or more known transmitted pilot sequences. Channel estimation methods have become more advanced, but generally comprise quite computational intensive processing. There may be a wish to provide a more efficient method and device for channel estimation.